1. Field of the Invention
The present invention relates generally to photography, and particularly to means in a foldable camera for preventing an exposure whenever the camera is folded and throughout each film transport cycle.
2. Description of the Prior Art
It has long been known to provide a foldable camera with means for preventing the camera shutter from being actuated when the camera is in its folded or closed condition. It has also been known to provide a camera with means for preventing its shutter from being actuated during a film transport cycle.
For example, German Pat. No. 644,612 discloses a reflex camera having a viewfinder cover that is hinged to the camera housing for movement from an open, viewing position to a closed position. As the cover is moved to its closed position, the shutter release member becomes blocked, or locked, to prevent actuation thereof when the viewfinder is not ready for use.
Similarly, U.S. Pat. No. 2,011,895 and German Utility Model No. 1,453,920 each disclose a foldable camera wherein the camera lens mount is movable from an extended, picture-taking position to a retracted, storage position. As the lens mount is moved to its retracted, storage position, the shutter release member becomes blocked to prevent actuation thereof when the camera is folded.
U.S. Pat. No. 2,117,971 also discloses a foldable camera wherein the lens mount is movable from an extended, picture-taking position to a retracted, storage position. The shutter mechanism in this camera is divided into two parts, one part including the shutter leaves and diaphragm, the other part including the mechanism for operating those members. The two parts are operatively engaged only when the lens mount is in its fully extended, picture-taking position. When the lens mount is in any other position, i.e., whenever the camera is not fully unfolded, the two parts are disengaged and the shutter is locked closed to preclude any opening movement thereof. Moreover, when the lens mount is in its fully retracted, storage position, the camera is fully folded and the shutter release member is inaccessible to the user. Also, the camera is provided with a shutter-cocking and film-winding lever which is manually reciprocable away from and back to its rest position against the camera body. The lever can be reciprocated only when the camera is at least partially unfolded. The first stroke of the lever cocks the shutter and starts winding the film. Additional strokes are required to wind the film sufficiently to place its next image area in position for exposure. After completion of the preceding exposure, the shutter release member is blocked until the shutter has been cocked and the lever returned to its rest position. The release member can then be actuated to release the shutter, and thereby effect another exposure, even though the lever has not yet been reciprocated enough times to move the next image area into position for that exposure. Thus, since the shutter release member is not blocked throughout a film transport cycle, any film image area can be exposed more than once.
U.S. Pat. No. 3,577,900 discloses a motorized camera wherein the lens mount is movable from an extended, picture-taking position to a retracted, storage position. In this camera, the externally accessible shutter release member is automatically retracted to its depressed position, without releasing the shutter, when the lens mount is moved to its retracted, storage position. Thus the shutter cannot be operated whenever the lens mount is so positioned. When the lens mount is moved to its extended, picture-taking position, the shutter release member is automatically extended to its operative position. After an unexposed film image area has been moved into position for exposure, the release member can be depressed to release the shutter. Upon automatic return of the release member to its extended position, a double-exposure-prevention mechanism blocks said member, and thereby prevents it from being depressed again, until the next unexposed film image area has been moved into position for exposure. Since the shutter release member is blocked throughout a film transport cycle, any one film image area cannot be exposed more than once. While this camera thus offers an advantage over that described in U.S. Pat. No. 2,117,971, the mechanism provided in this camera for automatically retracting the release member to its depressed position without releasing the shutter when the lens mount is retracted to its storage position, and for automatically blocking the release member to prevent shutter-releasing movement thereof to said depressed position during a film transport cycle, is complex and costly to manufacture.
Of interest also is U.S. Pat. No. 3,714,879, which discloses a foldable, motorized, reflex camera camera of the processing type. This camera is foldable from an erect, picture-taking configuration to a folded, or collapsed, configuration suitable for storing and carrying. At no time is its shutter release member blocked. When the camera is fully folded, its release member is covered and thereby rendered inaccessible. Throughout a film transport cycle the release member, though depressable, is electrically rendered ineffective to operate the camera's electronic shutter. Thus, this camera relies on covering its release member to prevent shutter-operating actuation thereof when the camera is folded, and on electrical control circuitry to prevent the shutter from operating if the release member is actuated during a film transport cycle.
A review of all the prior art discussed above indicates a long-felt but hitherto-unresolved need for a simple and reliable undesired-exposure-prevention device in a foldable camera; a device that automatically and positively prevents shutter operating movement of the camera's shutter operating member both when the camera is folded and throughout each film transport cycle; a device that performs that function without having to move the shutter operating member from its normal, operative position; a device that performs that function without having to cover the shutter operating member or otherwise render it inaccessible; a device that performs that function without having to use electrical or other means for rendering normal movement of said member ineffective to operate the shutter.